IA

Wow, now your asking for a variety of answers. :) However, I had the same exact question about a year ago, and the primary answer is simple... Process, Technology and People
The vague definition is:
An Information Architect is a high level designer that uses information as building material.

Well, here are some links for your review, and I wish you the best in your search.

http://www.webmasterbase.com/article.php?aid=302&pid=0

http://www.dcc.uchile.cl/~rbaeza/manifest/infarch.html
http://www.eyearchitect.com/tribute/

What is an information architect?

"From my own experience, I would say that the practitioners are professionals, versed in every aspect of web design, adept communicators, and gifted visualizers - they are people who eat, sleep and dream web design and structure. But you can't put that on the job description."

- Bebo White (the designer who built the first web server in North America)

Information architect: an individual who organises the patterns inherent in information, structuringthe systems that will define the next century."

- The Information Architects Mailing List

How about..."the science of figuring out what you want your site to do and then constructing a blueprint before you dive in and put the thing together".

http://www.atl.ualberta.ca/downes/threads/mm1.htm

REMOVE SPACES from the pasted URL

First and foremost it IT NOT ABOUT THE WWW! AS an IA/DBA I get annoyed seeing some web designers (and companies) call themselves IAs, and define Information Architecture as the "properly thought design of a web site". IA's have been around way longer than the web. Look at the root words Information + Architect. The man credited with coining the term "Information Architecture", Richard Saul Wurman described it this way in his 1996 book "Information Architects". 1. the individual who organizes the patterns inherent in data, making the complex clear
2. a person who creates the structure or map of information which allows others to find their personal paths to knowledge
3. the emerging 21st century professional occupation addressing the needs of the age focused upon clarity, human understanding, and the science of the organization of information

And I agree this is the clearest and most concise description I've yet to see.